Gas production apparatus

Abstract

A gas production apparatus is provided which include: an element laminate having a light receiving section on one side and a conductive substrate on the other, in which laminate a plurality of elements, each including a semiconductor thin film with pn junction, are so laminated on each other as to connect in series to each other; a hydrogen gas generator formed on a surface of a first element located on the light receiving section side; a first electrolysis chamber including the hydrogen gas generator; an oxygen gas generator formed on a back surface of the conductive substrate; a second electrolysis chamber including the oxygen gas generator; and an ion-permeable but gas-impermeable diaphragm provided between the first and second electrolysis chambers.

What is claimed is: 
     
         1 . A gas production apparatus, comprising:
 an element laminate in which a plurality of elements, each having a light receiving portion and including a semiconductor thin film with pn junction, are so laminated on each other as to connect in series to each other;   a hydrogen gas generator which is formed on a surface of a first element among the plurality of elements and generates hydrogen gas, the first element being positioned at one end of the element laminate;   a first electrolysis chamber which includes the hydrogen gas generator and contains an aqueous electrolytic solution in contact with the hydrogen gas generator, and the hydrogen gas generated;   an oxygen gas generator that is formed on a back surface of a conductive substrate, on which the semiconductor thin film of a second element among the plurality of elements is formed, and generates oxygen gas, the second element being positioned at another end of the element laminate;   a second electrolysis chamber which includes the oxygen gas generator and contains an aqueous electrolytic solution in contact with the oxygen gas generator, and the oxygen gas generated; and   a diaphragm which is ion-permeable but gas-impermeable, and is provided between the first electrolysis chamber and the second electrolysis chamber.   
     
     
         2 . The gas production apparatus according to  claim 1 , wherein the hydrogen gas generator is provided with a hydrogen generation surface, and the hydrogen generation surface is formed on a surface of the semiconductor thin film of the first element. 
     
     
         3 . The gas production apparatus according to  claim 1 , wherein the first element is composed of a plurality of sub-elements, and the plurality of sub-elements are disposed on the second element discretely with respect to the second element. 
     
     
         4 . The gas production apparatus according to  claim 3 , wherein the plurality of sub-elements each have an element area smaller than that of the second element. 
     
     
         5 . The gas production apparatus according to  claim 1 , wherein:
 the oxygen gas generator is provided with an oxygen generation surface formed on the back surface of the conductive substrate; and   the oxygen generation surface is inclined upward along a flow direction of the aqueous electrolytic solution in the second electrolysis chamber.   
     
     
         6 . The gas production apparatus according to  claim 1 , wherein the semiconductor thin film includes a CIGS-based compound semiconductor. 
     
     
         7 . The gas production apparatus according to  claim 1 , wherein the semiconductor thin film includes a CZTS-based compound semiconductor. 
     
     
         8 . The gas production apparatus according to  claim 1 , wherein the semiconductor thin film has an absorption wavelength edge equal to or greater than 800 nm. 
     
     
         9 . The gas production apparatus according to  claim 1 , further comprising a hydrogen generation promoter provided on the hydrogen generation surface of the hydrogen gas generator. 
     
     
         10 . The gas production apparatus according to  claim 9 , wherein the hydrogen generation promoter is platinum.